Preparation method of PLA composite fabric

Abstract

The invention discloses a preparation method of a PLA (polylactic acid) composite fabric, which comprises the following steps: applying a flame-retardant layer on the surface of a PLA substrate fabric, and compounding with a functional film to prepare the fabric with flame-retardant, waterproof and moisture-permeable functions. The preparation method comprises the following steps: 1) applying a flame-retardant coating agent to the surface of a PLA base material fabric: slowly adding phosphorus-containing quaternary ammonium salt organosiloxane sol into a polyurethane emulsion, and uniformly stirring to prepare the flame-retardant coating agent; the surface (single face) of the PLA base material fabric is coated with a flame-retardant coating agent. And 2) compounding the base material fabric and the functional film: (1) gluing: firstly coating the surfaces of the base material fabric and the functional film with a polyurethane hot melt adhesive, and (2) laminating: flatly overlapping the fabric and the film together, then transferring into a pressing machine, then setting the hot pressing temperature and the hot pressing time, and after the temperature is reached, pressing to finish hot pressing and laminating to prepare the PLA composite fabric. The phosphorus-containing quaternary ammonium salt organosiloxane sol is an efficient halogen-free flame retardant integrating phosphorus, nitrogen and silicon elements, and has a good flame-retardant synergistic effect.

Description

Technical Field

[0001] The present invention relates to a preparation method of a PLA composite fabric, belonging to the field of functional textile fabrics. Background Art

[0002] PLA (polylactic acid) is a completely biodegradable polymer, which has many advantages such as safety, environmental protection, and strong mechanical properties, and has a wide range of applications in the textile and clothing fields. However, PLA has the disadvantage of being extremely flammable, with an LOI value of only about 19%, and it is prone to produce molten droplets with fire during the combustion process, which severely limits its application. In order to promote the application of PLA fabrics and improve the fire safety of PLA fabrics, it is necessary to improve the flame retardant performance of PLA fabrics. Summary of the Invention

[0003] The object of the present invention is to provide a preparation method of a PLA composite fabric, which first applies a flame retardant layer on the surface of a PLA base fabric, and then composites it with a functional film to make a fabric with functions such as flame retardancy and waterproofness.

[0004] To achieve the above object, the present invention adopts the following technical solutions.

[0005] A preparation method of a PLA composite fabric includes the following steps:

[0006] Apply a flame retardant coating agent on the surface of the PLA base fabric;

[0007] Composite the base fabric with a functional film to make a PLA composite fabric;

[0008] In terms of parts by mass, the flame retardant coating agent is composed of 28 parts of a phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts of a polyurethane emulsion, and 0.1 - 2 parts of a thickener.

[0009] The specific preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane sol is as follows: Add 40 parts of tetraethyl orthosilicate (TEOS), 2 parts of acetic acid, 10 parts of deionized water, and 240 parts of ethylene glycol monomethyl ether into a container, and stir at room temperature for 30 minutes for pre-hydrolysis; then add 18 parts of a phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidoxypropyltrimethoxysilane (KH560) into the above container, and stir and react at room temperature for 12h to obtain a phosphorus-containing quaternary ammonium salt organosiloxane sol.

[0010] The preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane is as follows:

[0011] Add 17.3 g of diethyl chlorophosphate and 50 mL of tetrahydrofuran to the S1 reactor. While introducing nitrogen for protection, continue to add 9 g of N,N-dimethylethanolamine and 3 g of triethylamine, and stir and react in an ice-water bath for 4 h. After the reaction is complete, perform vacuum distillation to remove the organic solvent tetrahydrofuran, and then perform suction filtration to obtain N,N-dimethylamine (triethyl phosphate).

[0012] In a reactor equipped with a stirrer, a condenser, and a thermometer, add 22.5 g of N,N-dimethylamine (triethyl phosphate), 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol, stir and mix evenly, and react under reflux at 70 °C. After the reactants become transparent, react for another 2 hours, and then remove isopropanol under the condition of 0.01 MPa to obtain a viscous liquid, which is a phosphorus-containing quaternary ammonium salt organosiloxane.

[0013] The functional film is a TPU film (thermoplastic polyurethane film) with a thickness of 0.012 - 0.015 mm.

[0014] The substrate fabric is compounded with the functional film. The specific steps are as follows:

[0015] ① Glue coating: First, coat the surfaces of the substrate fabric and the functional film with hot melt adhesive.

[0016] ② Film lamination: The fabric and the film are stacked flat together, and then moved to a hot press. Then, set the hot pressing time and hot pressing temperature. After the temperature reaches, perform hot pressing to complete the hot press lamination and make a PLA composite fabric.

[0017] The hot melt adhesive is polyurethane hot melt adhesive, and the coating amount is 30 - 40 g / m 2 .

[0018] A preparation method of a PLA composite fabric disclosed by the present invention is to first apply a flame retardant layer on the surface of a PLA substrate fabric, and then compound it with a functional film to make a fabric with functions such as flame retardancy, waterproofness, and moisture permeability.

[0019] The phosphorus-containing quaternary ammonium salt organosiloxane sol is a high-efficiency halogen-free flame retardant integrating phosphorus, nitrogen, and silicon elements, and has good flame retardant synergistic effects. Through the separate cross-linking of covalent bonds (-Si-O-C- bonds) and epoxy groups, the coating has good mechanical properties, and the coating has a smooth surface, good transparency, excellent durability, and firmness.

[0020] The polyurethane undergoes a cross-linking reaction with the sol to enhance the toughness and durability of the coating film. Specific embodiments

[0021] The technical solutions of the present invention will be described in detail below through specific embodiments.

[0022] The present invention discloses a preparation method of a PLA composite fabric, comprising the following steps:

[0023] Apply a flame retardant coating agent on the surface of the PLA base fabric;

[0024] Compound the base fabric with a functional film to make a PLA composite fabric.

[0025] Coat a flame retardant coating agent layer on the surface of the PLA base fabric, and compound the back side with a film.

[0026] The flame retardant coating agent is composed of a phosphorus-containing quaternary ammonium salt organosiloxane sol, a polyurethane emulsion, and a thickening agent. By mass, 28 parts of the phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts of the polyurethane emulsion, and 0.1 - 2 parts of the thickening agent are used. An appropriate amount of the thickening agent is used to adjust the viscosity of the flame retardant coating agent system to 6000 - 8000 mPa·s. The thickening agent is non-ionic, such as the non-ionic thickening agent YC-100 (Anhui Yuanchen New Material Technology Co., Ltd.).

[0027] The functional film is a commercially available TPU film (thermoplastic polyurethane film) with a thickness of 0.012 - 0.015 mm, which can endow the fabric with good waterproof performance.

[0028] The specific preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane sol is as follows: Add 40 parts of tetraethyl orthosilicate (TEOS), 2 parts of acetic acid, 10 parts of deionized water, and 240 parts of ethylene glycol monomethyl ether into a container, and stir at room temperature for 30 minutes for pre-hydrolysis; then add 18 parts of the phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidoxypropyltrimethoxysilane (KH560) into the above container, and stir and react at room temperature for 12 h to obtain the phosphorus-containing quaternary ammonium salt organosiloxane sol.

[0029] The preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane is as follows:

[0030] Add 17.3 g of diethyl chlorophosphate and 50 mL of tetrahydrofuran into the S1 reactor, and at the same time introduce nitrogen for protection. Then continue to add 9 g of N,N-dimethylethanolamine and 3 g of triethylamine, and stir and react in an ice-water bath for 4 h. After the reaction is complete, carry out vacuum distillation to remove the organic solvent tetrahydrofuran, and carry out suction filtration to obtain (triethyl phosphate)N,N-dimethylamine;

[0031] In the S2 reactor equipped with a stirrer, a condenser, and a thermometer, add 22.5 g of (triethyl phosphate)N,N-dimethylamine, 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol, stir and mix evenly, reflux and react at 70 °C. After the reactants become transparent, react for another 2 hours, and then remove isopropanol under the condition of 0.01 MPa to obtain a viscous liquid, which is the phosphorus-containing quaternary ammonium salt organosiloxane.

[0032] The reaction formula for preparing the phosphorus-containing quaternary ammonium salt organosiloxane is as follows:

[0033]

[0034] The preparation method of the polyurethane emulsion is as follows:

[0035] Add polypropylene glycol (molecular weight 2000), isophorone diisocyanate and dibutyltin dilaurate to a reactor equipped with a stirrer, a condenser and a thermometer, and react at 90 °C for 2 h; add dimethylolpropionic acid and N,N-bis(2-hydroxyethyl)-3-methylsilane (as shown in Formula 3), and react for 1 h; then add methyl ethyl ketoxime and react for 2 h. Cool down to room temperature, add triethylamine for neutralization, and add deionized water and stir at high speed for 30 min to obtain a blocked polyurethane emulsion.

[0036] The molar ratio of isophorone diisocyanate to polypropylene glycol is 1.8 - 1.5:1, the molar ratio of N,N-bis(2-hydroxyethyl)-3-methylsilane to isophorone diisocyanate is 0.1:1, and dimethylolpropionic acid accounts for 5 - 8% of the total mass of isophorone diisocyanate and polypropylene glycol.

[0037]

[0038] The composite of the substrate fabric and the functional film is carried out according to the following specific steps:

[0039] ① Glue coating: First, coat the surface of the substrate fabric and the functional film with hot melt adhesive.

[0040] ② Film laminating: Stack the fabric and the film flatly together, then move them to a hot press. Then set the hot pressing time and hot pressing temperature. After the temperature reaches, carry out hot pressing to complete the hot press film lamination and make a PLA composite fabric.

[0041] The hot melt adhesive is a polyurethane hot melt adhesive, a commercially available product. The coating amount of the hot melt adhesive on the surface of the fabric and the functional film is 30 - 40 g / m 2 .

[0042] The PLA substrate fabric used in the example has warp and weft yarns: PLA and cotton fiber blended yarn, composition: 50% PLA + 50% cotton, warp and weft density: 450×240.

[0043] Pretreatment of the substrate fabric by scouring: Put the substrate fabric into the pretreatment solution → heat up to 100 °C and keep it for 30 min → cool down and wash with water; the pretreatment solution contains 4 g / L soda ash, 2 g / L scouring agent, 2 g / L chelating dispersant, and the rest is water, and the bath ratio is 1:8.

[0044] The scouring agent, chelating dispersant, etc. involved in the pretreatment steps of scouring are all commercially available conventional products.

[0045] Example 1:

[0046] A preparation method of a PLA composite fabric, comprising the following steps:

[0047] 1). Applying a flame retardant coating agent on the surface of the PLA base fabric: Slowly add a phosphorus-containing quaternary ammonium salt organosiloxane sol into a polyurethane emulsion, stir evenly, ultrasonically disperse for 30 minutes, and then adjust the viscosity to 6000 - 8000 mPa·s with a non-ionic thickener YC-100 to obtain a flame retardant coating agent; Coat the flame retardant coating agent on the surface (single side) of the PLA base fabric at 100 - 120 g / m 2 , dry at 100°C for 2 min and cure at 160°C for 30 s; By mass, the flame retardant coating agent contains 28 parts of phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts of polyurethane emulsion, and 0.1 - 2 parts of thickener.

[0048] 2). Composites the base fabric with a functional film:

[0049] ① Gluing: First, coat the surface of the base fabric and the functional film with a polyurethane hot melt adhesive, and the coating amount of the hot melt adhesive is 30 - 40 g / m 2 ;

[0050] ② Film laminating: Stack the fabric and the film flatly together, then move them to a hot press, and then set the hot pressing temperature at 105°C and the hot pressing time at 30 s. After the temperature reaches, perform hot pressing, with a winding pressure of 3 kg and a laminating speed of 10 m / min to complete the hot press film laminating and make a PLA composite fabric.

[0051] Perform performance tests such as flame retardancy and waterproofness on the PLA composite fabric prepared by the method of the example.

[0052] Flame retardant performance of the PLA composite fabric: Afterflame time is 0 s, smoldering time is 0 s, damage length is 8.5 cm. The flame retardant performance test refers to "GB / T 5455 - 2014 Determination of damage length, smoldering and afterflame time of textile burning performance in the vertical direction".

[0053] Waterproof performance of the PLA composite fabric:

[0054] Hydrostatic pressure resistance: 1387 mmH2O. The test method refers to "GB / T4744 - 2013 Testing and evaluation of waterproof performance of textiles - Hydrostatic pressure method".

[0055] Water repellency grade: 4 - 5 levels. The test method refers to "GB / T 4745 - 2012 Testing and evaluation of waterproof performance of textiles - Water repellency method".

Claims

1. A preparation method of a PLA composite fabric, comprising the following steps: Applying a flame retardant coating agent on the surface of the PLA base fabric; Compounding the PLA base fabric with a functional film to make a PLA composite fabric; By mass, the flame retardant coating agent is composed of 28 parts of a phosphorus-containing quaternary ammonium salt organosiloxane sol, 70 parts of a polyurethane emulsion, and 0.1 - 2 parts of a thickening agent.

2. The preparation method of a PLA composite fabric according to claim 1, characterized in that: For the phosphorus-containing quaternary ammonium salt organosiloxane sol, the specific preparation method is to add 40 parts of tetraethyl orthosilicate, 2 parts of acetic acid, 10 parts of deionized water, and 240 parts of ethylene glycol monomethyl ether into a container, and stir at room temperature for 30 minutes for pre-hydrolysis; then add 18 parts of the phosphorus-containing quaternary ammonium salt organosiloxane and 2 parts of 3-glycidoxypropyltrimethoxysilane into the above container, and stir and react at room temperature for 12 h to obtain the phosphorus-containing quaternary ammonium salt organosiloxane sol.

3. The preparation method of a PLA composite fabric according to claim 2, characterized in that, The preparation method of the phosphorus-containing quaternary ammonium salt organosiloxane is as follows: S1 Add 17.3 g of diethyl chlorophosphate and 50 mL of tetrahydrofuran into a reactor, while introducing nitrogen for protection, then continue to add 9 g of N,N-dimethylethanolamine and 3 g of triethylamine and stir and react in an ice bath for 4 h. After the reaction is complete, distill under reduced pressure to remove the organic solvent tetrahydrofuran, and filter to obtain (triethyl phosphate)N,N-dimethylamine; S2 In a reactor equipped with a stirrer, a condenser, and a thermometer, add 22.5 g of (triethyl phosphate)N,N-dimethylamine, 24 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 140 g of isopropanol, stir and mix evenly, reflux and react at 70 °C. After the reactants become transparent, react for another 2 hours, and then remove isopropanol under the condition of 0.01 MPa to obtain a viscous liquid, which is the phosphorus-containing quaternary ammonium salt organosiloxane.

4. The preparation method of a PLA composite fabric according to claim 1, characterized in that: The functional film is a TPU film with a thickness of 0.012 - 0.015 mm.

5. The preparation method of a PLA composite fabric according to claim 1, characterized in that, The compounding of the PLA base fabric and the functional film specifically comprises the following steps: ① Glue coating: First, coat the surfaces of the base fabric and the functional film with hot melt adhesive. ② Film laminating: Stack the fabric and the film flatly together, then move them to a hot press, and then set the hot pressing time and hot pressing temperature. After the temperature reaches, perform hot pressing to complete hot press film laminating to make a PLA composite fabric.

6. The preparation method of a PLA composite fabric according to claim 5, characterized in that: The hot melt adhesive described above is polyurethane hot melt adhesive, and the coating amount is 30 - 40 g / m 2 .

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